In 1.5 to 2.0% of patients with AMI referred for primary percutaneous coronary intervention, the left main trunk is identified as the culprit vessel. Among the congenital coronary anomalies, an anomalous origin of the left main trunk from the right sinus of Valsalva is very rare. A 73-year-old patient with lateral acute myocardial infarction was referred to primary angioplasty. The initial angiogram showed an anomalous origin of the left main from the right coronary artery, apparently with a septal course, with an angiographic image of intraluminal thrombus; in addition, a severe lesion was present at the distal right coronary artery. The left main and right coronary arteries were successfully treated with direct stenting. The subsequent clinical course during hospitalization was uneventful, and the patient was discharged alive.